PLX Rewires Datacenter for Express

SANTA CLARA, Calif. -- PLX Technology recently showed a developer's system enabling PCI Express as the first-level switch inside a computer rack. The 1U switch is the company's latest effort to rewire datacenters with its silicon, significantly undercutting the costs of Ethernet and Infiniband.

The system is essentially a 96-port PCI Express Gen 3 switch. It can deliver connections running at the equivalent of Infiniband QDR (about 10 Gbit/s) among a rack full of servers and storage arrays. That's an order of magnitude faster than the Gigabit Ethernet used inside most datacenter racks today.

PLX also says its setup shaves costs. For example, Infiniband requires each server to use an adapter costing about $500 and consuming about 8W, but the PLX approach needs only a repeater chip costing less than $10 and burning less than half a Watt -- slightly less than today's Gigabit Ethernet in cost and power.

There's a catch. Today's datacenters rely on a wealth of production-tested and tuned software for networking and management inside the rack. Today's code is based on Ethernet and Infiniband, not PCIe.

PLX has a driver for its PCIe chips that would provide the foundation for the networking and management software, but the driver has yet to be tested and tuned. In addition, software needs to be ported to the PLX platform.

The system, shown at the annual PCI SIG developer's conference here (see below), is not ready for prime time. It requires a PCIe adapter card on each server. A version requiring only cheap repeater chips is still in development, and PLX will not say when that version will be ready.

The developer's system shown at the PCI SIG event still requires a full network interface card on each server.

However, the company does say multiple Tier 1 customers are testing the beta system shown at the event. Server engineers at Facebook said last year that one of their long-term goals is to get the Ethernet chips off their server motherboards to reduce cost and complexity. The PLX solution could enable that.

The system requires three large 32-port PCIe Gen 3 switch chips from PLX, plus a system management processor. It sports two slots for expansion cards to support uplinks to second-tier Ethernet or Infiniband switches that would link multiple racks.

PCI Express is getting quite a lot of traction, so it'll be interesting to see how it does with PLX's adapter-card approach. It's got the speed and low power. Infiniband may feel the squeeze. Interesting progress by PLX: Thanks for the update Rick.